Arch construction.



L'. BERNHARD. ARCH CONSTRUCTION.

APPL1CATION FILED FEB. 10. I915.

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ARCH CONSTRUCTION.

APPLICATION FILED FEB. I0. 1915.

Patented Nov. 2, 1915.

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LOUIS B ERNHARD, OF BOSTON, MASSACHUSETTS.

ARCH CONSTRUCTION.

Specification of Letters Patent.

Patented Nov. 2, MM 5.

Application filed FebruarylO, 1915. Serial No. 7,436.

will not crumble and fall to pieces on account .of expansion and contraction. This is particularly important n the case of boilers because if the arch, or portionsthereof fall, a portion of theeXterio-r of the boiler above the water level will be exposed to intense heat which is likely to result in 4 bursting of the boiler. e

. My invention consists partly in the combination of a bridge and an arch beneath the bridge with spacebetween the bridge and arch to allow for expansion of the latter.

A feature of my invention consists in an outer and an inner arch. the inner arch be-. ing supported by the outer but wlth provision for relative movement of the inner arch so that it may expand and contract and as supporting means I prefer hangers or binders preferably in the form of double wedges.

Another feature of my invention is the use of magnesia or equivalent material to act not only as a support for building the outer arch, in case the latter is made of a number of elements, such as bricks, but also to act as a heat insulator and as a provider of space for the movement of the lower arch.

A feature of my invention consists in arranging the bricks or other elements of the arch diagonally so as to prevent the applit0 cation of expansive pressure at right angles to the supporting walls and this feature. of my invention, although particularly adapted for locations in which much expansion and contraction of the arch is had is also use fill in any arch construction.

Other features of my invention will be pointed out below.

In the drawings: Figure 1 is a rear elevation partly in section of a boiler setting embodying my invention, Fig. 2 is a lan, partly in section, of the setting; and igs.

3 and 4m enlarged sectional details.

Walls A A are as usual and lined with fire bricks B B as usual, the clean-out opening below shown at D. Boiler E is provided.

with fuse plug F, preferably a few inches below the arch so that normally the water in the boiler will be a few inches above the plug and at the height of the arch.

The inner arch consists of a number of firebricks (ir-and hangers or binders H also of firebrick. Upon this inner arch I spread a layer of magnesia K or other equivalent material and this serves as a frame upon which the outer arch is built, the outer arch consisting of ordinary bricks M and being connected to the inner arch by the binders or hangers H. The ordinary brickwork M is provided above the outer arch and is sup ported by' it, the brickwork M and the bricks forming the bridge.

' The arch as first built is illustrated in Fig. the hangers H, which are preferably wedge shaped at both ends with straight portions adjacent to the magnesia, being a tight fit in the lower arch but a slightly loose fit in the upper arch.

When the boiler is heated the magnesia contracts, its moisture being driven out, and this leaves a space is so that the inner arch may expand toward the outer arch. At this time the binders being of firebrick will expand slightly possibly to the position shown in dotted lines in Fig. 4-.

I preferably provide any suitable raised caps N N to allow for expansion of binders H and to cover and protect them.

hen the inner arch contracts it will I move away from the outer arch but the magnesia remains in its contracted condition so that space it remains available for the next expansion of the inner arch. contraction of the inner arch the binders will contract and be lowered and, the lower wedge will spread the inner arch slightly holding it firmly against its abutments. The binders H have a reinforcing and supporting function as to the inner arch and also during the movements of the inner arch a. steadying function.

In'Fig. 2 I illustrate the diagonal arrangement of the bricks or elements of the inner arch this construction providing pressure corner-wise and doing away with direct pressure against the side walls which is a matter of great importance particularly in cases where there are great changes on account of the presence or absence of heat.

It will be observed that I really provide an -arch in two parts, the outer part being non-expansible in its miture and also insulated by the magnesia and the inner part be- During the.

ing expa-nsible but without possibility of falling apart or crumbling with the great advantage, among others, of preventing exposure of any portion of the boiler which for the movements of the lining; and means.

connecting the bridge and lining to support the latter, but permitting relative movement between the bridge and lining, said means moving outwardly when the lining expands but supporting the lining during the expansion. v

2. An arch construction comprising an outer arch of ordinary brick; an inner arch of iirebrick spaced from the outer arch; and binders at intervals connecting the two arches, but permitting relative movement between them, said binders supporting the inner arch during its expansion and moving outwardly during said expansion;

3. An arch construction for boiler settings and the like comprising an outer arch of ordinary brick; an inner arch of firebrick;

a layer of magnesia or the like on said inner arch, said layer being spaced from the outer arch. to permit movement of the inner arch; and binders at intervals connecting the two arches but permitting relative movement between them, said binders supporting the inner arch during its expansion and moving outwardly during said expansion.

at. An arch construction comprising an outer arch; an inner expansible arch spaced from the outer arch; and binders connecting the two arches and having sliding connection with the outer arch, each binder being of a double-wedge shape.

5.--An arch construction comprising an outer arch; an inner expansible arch spaced from the outer arch; and binders connecting the two arches but permitting relative movement between them, each binder consisting of an outwardly slopingwvedge at one end, an outwardly sloping wedge at the other end and a straight central portion.

6. An -arch construction made from elements diagonally disposed so 'as to prevent the expansion ofthe arch from applying pressure in a direction perpendicular to the side walls of the structure, the set of ele ments extending from two diagonally opposite corners being parallel, and the set of elements extending from the other two diagonally opposite corners being at right angles to the first set.

7. An arch construction comprising an outer arch; an inner expansible arch spaced from the outer arch; and binders connecting the two arches and snpporting the inner archhduring its expanslon'and having sliding connection with :the' outer arch, said binders moving outwardly. during the expansion of the inner arch.

8. An arch construction comprising an outer arch; an inner expansible arch spaced from the outer arch; and, means connecting the two arches but permitting relative movement between them, said means support ng the inner arch during its expans on and mov ing outwardly during said expansion.

9. An arch construction comprising an inner arch; an outer arch of material less expansible under the'action of heat than the material of said inner arch; and intermediate material filling the space between said arches, said intermediate material being con tractile underthe action of heat.

10. An arch construction comprising an inner arch of fire-brick; an outer arch of ordinary brick; and .magnesia filling the space between said arches, said magnesia being contractile under the action of heat.

3 LOUIS BERNHARD.

Witnesses: GnoReE A. Roonwnu), Gno. N. Goonenn, 

